Oak board with Estun Servo 410/411 errors

[bcarlsen]

Hi all. My bridgeport conversion is now running...sort of. I'm using an Oak board with Estun EMG drive motors in velocity mode. I've configured the Estun drives for velocity mode and set all the appropriate CNC 11 parameters. Everything checks out until I try to move or jog the motors from CNC 11. Then I get error 410 and sometimes 411. What I think is happening, is that the encoder and motor move signals are inverted. I verified that by noting the movement of the motor spindle verses DRO output for various G01 commands. The motor always moves in the opposite direction it should (it only moves a small amount before the 410 error kicks the E-stop).

I found a parameter in the Estun controller (Pn001.0) which supposedly will invert the motor direction without changing the encoder direction. I tried this, but the encoder signals invert also. My feeling now, is that I should try flipping two of the motor drive leads to force the motor to reverse without effecting the encoder. I'm just a bit nervous doing that as I don't want to wreck the drive and/or motor. Is this a reasonable next step?

I've attached a report file from the CNC 11.

Thanks,
Bill

[cnckeith]

i alerted centroid tech support to your post, help is forthcoming.

[Centroid_Tech]

What happens when you try pressing F3(MDI)? If the same thing happens, try inverting the analog speed signals to the Estun drive. Out of curiosity, did you purchase the Estun OAK interface cables from Centroid or did you build your own?

[Centroid_Tech]

Looking more deeply into the report that you posted, I see a lot of encoder related error messages. I would check your encoder wiring from the drive to the OAK board. I also see that parameter 356 is set to 0 and it should be set to 250.

[bcarlsen]

1. The cables I am using were made by Centroid.

2. I changed parameter 356 to 250 with no effect. I am not using an MPG pendant.

3. The errors you saw from the encoders were due to my fiddling with the Estun drives (power off, then on to set parameters) while CNC11 was running.

4. The encoders on all axes are reading out nice clean numbers with no apparent noise. The numbers make sense in terms of counts per revolution. The absolute encoder counts move in the correct direction on all axes when turning the shafts by hand (moving a motor counterclockwise when facing the motor face, causes the absolute encoder counts to increase).

5. I've checked jog operation using the Estun drive (Fn002) on all axes and the motors move correctly (plus button moves motor CCW, minus button moves motor CW). If CNC 11 is on, the motors are released, and I jog using the Estun drive, the DRO readout moves correctly and cleanly (plus button DRO increases, minus button DRO decreases). Also, the absolute encoder counts move correctly (plus button counts increase, minus button counts decrease).

6. When I run MDI and then input "G1 Y1" (move +1") I get error 410 from CNC11 and the Oak board flashes error "8" on the numeric LED. Error 8 on the Oak implies too many interrupt requests. Where would these interrupts be coming from?

7. Before reversing the analog speed signal wires, I tried the following: I set up the Estun drive to report the "speed reference input" using Un001. I then used MDI to command "G1 Y10" (move +10 inches). The following happened:
a) The Estun drive reported a momentary +2000 for speed reference input. (This seems to say the Oak board is sending the right polarity speed signal)
b) CNC 11 reported a motor overload (red bar below y axis drive) then executed an E-stop.
c) CNC 11 then reported Error 410
d) Oak board reported Error 8 on the numeric LED
e) the DRO readout on CNC 11 moved more negative (this seems wrong)

If I then try MDI command "G1 Y-10" (move -10 inches), the following happens:
a) The Estun drive reports a momentary -2000 (approx number) for speed reference (This seems to say the Oak board is sending the right polarity speed signal)
b) CNC 11 reports motor overload and then E-stop
c) CNC 11 reports Error 410
d) Oak reports Error 8
e) the DRO readout on CNC 11 moves more positive (this seems wrong)

Given that we are getting "too many interrupt requests" I'm not sure we should proceed in reversing the speed ref signals yet, without fixing the interrupt problem first. So, I haven't tried switching wires (dis-assembling the connector might be tough...haven't looked inside yet). I will do that next if you feel that is the next thing to try.

[cncsnw]

It is parameter 365 that needs to be set to ca. 250ms, not parameter 356.

[cncsnw]

If you do still suspect a reference direction / encoder direction mismatch, you could test-jog the motor in an uncontrolled open-loop mode from the Centroid control.

This should be done with the motor secured and uncoupled. Otherwise, there are more ways to get in trouble in this procedure than I am prepared to enumerate.

With the motor secured and uncoupled from the machine:
Go to the F4/PID Configuration screen.
Set Kp, Ki and Kd all to 0.0.
Leave your Kv1 value in place (e.g. 80)
Press Ctrl-V to disable stall detection
Choose Slow, Continuous jog mode
Turn the feedrate override knob down to ca. 10%
Press and hold the plus jog key.
Watching the motor and the "PID Out" value, turn the override up as needed to get the motor to move a few turns.
Try the same thing with the minus jog key.

Does a positive PID Out value correspond to positive-going encoder counts?
Does a negative PID Out value correspond to negative-going encoder counts?

Note that, if you have Direction Reversal set on an axis, then the plus jog key will command negative movement, and vice versa.
If you do not have Direction Reversal set, then plus is plus and minus is minus.

When done testing, press Emergency Stop; press Ctrl-V again to re-enable stall detection; and put your Kp, Ki and Kd values back.

[Centroid_Tech]

The issue is that your max rate is set too high. Based on the pitch and the encoder counts/rev setting of your axis the maximum speed that your axis can handle is 109 in/min. 72,000,000 counts/min / (pitch * encoder counts/rev). In your case, it would be 72,000,000 counts/min / (10 revs/in * 25536 counts/rev) which is 72,000,000 counts/min / 655,360 counts/in which is roughly 109 in/min.

[bcarlsen]

OK, I've made some progress. I changed the counts per revolution output on the Estun driver Un200 = 8000/rev, and also the counts/rev number in CNC11 to 32000 counts/rev and we no longer get excess interrupts from the Oak board (Err 8). We still get error 410, however.

I then took cncsnw's advice and disabled stall detection and then checked the PID out signal vs. absolute encoder counts. Here's a summary of what I saw:

Jog plus then:
a) motor turns CW
b) PID out = +10
c) absolute counts decrease
d) Un001 input monitor on Estun drive = +210
e) DRO readout decreases

Jog minus then:
a) motor turns CCW
b) PID out = -10
c) absolute counts increase
d) Un001 = -210
e) DRO readout increases

It's beginning to look like the analog speed signal from the Oak board needs to be reversed. If that is the case, is there any way to do it in software? Changing wires on the connector is not going to be very pleasant.

[bcarlsen]

OK. I got it working! The Estun servo drives were not configured properly. The mistake I made was not doing a full reset on each Estun drive (Fn001), first, before setting things up. Just to recap:

1) The counts/revolution output from the Estun was too high for the Oak board. Lowering Pn200 to 8000 fixed that error (Error 8 from the Oak board).

2) Be sure to do a full reset using Fn001 before setting up the Estun drive.

Thanks all for your time and help.

Best Regards,
Bill